1. Field of the Invention
Embodiments of the present invention relate to an apparatus for inspecting a glass substrate, and more particularly, to an apparatus for inspecting a glass substrate by optical detection.
2. Description of the Prior Art
A glass substrate that is used to fabricate a flat panel display, such as a TFT-LCD (Thin Film Transistor-Liquid Crystal Display), a PDP (Plasma Display Panel), an EL (Electro Luminescent) device, or the like, is fabricated through a forming process for forming melted glass, which is melted in a glass melting furnace, into a flat panel, and a cutting process for cutting a glass substrate to suit a predetermined standard, and the fabricated glass substrate is transported to a machining line for a machining process.
In the above-described forming, cutting, and machining processes of the glass substrate, many defects, for example, such as size error, chipping, crack, unchampering, unbevel, over-bevel, and bevel chip, may occur on the glass substrate. Further, in a handling process for loading or transporting the glass substrate after the forming, cutting, and machining processes of the glass substrate, damage of the glass substrate may also occur.
The defects of the glass substrate may be directed to deterioration of the picture quality of the flat panel display including the glass substrate. For example, if the defect occurs on a display area of the flat panel display, the display quality of the flat panel display may be deteriorated.
Further, the glass substrate may be completely destroyed during the fabricating process of the flat panel display due to the defects. For example, in order to stick photoresist onto the glass substrate in a color filer fabricating process, a heat treatment process is performed with respect to the glass substrate at a temperature of more than 220° C. for 30 to 40 minutes in an oven. At this time, the glass substrate having the defects may be unable to endure the above-described conditions and may be completely destroyed. If the glass substrate is completely damaged and breaks into fragments, it is required to stop the heat treatment process, to cool and clean the oven, to put a new glass substrate in the oven, and to heat the oven again to restart the heat treatment process. Defects of the glass substrate thus cause waste of time and costs. Further, particles of the completely destroyed glass substrate may stick to the inside of the oven to cause continuous deterioration of the oven performance. In general, more than 40 glass substrates are simultaneously treated in the oven. If any one of the glass substrates is destroyed, the remaining glass substrates may also be affected to cause all the glass substrates put in the oven to be discarded.